Added initial command return support

src/main/java/net/minestom/server/command/CommandManager.java

@@ -27,6 +27,7 @@ import org.apache.commons.lang3.StringUtils;
 import org.apache.commons.lang3.tuple.Pair;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import org.jglrxavpok.hephaistos.nbt.NBTCompound;
 
 import java.io.BufferedReader;
 import java.io.IOException;
@@ -45,6 +46,7 @@ public final class CommandManager {
 
     private volatile boolean running = true;
 
+    private final ServerSender serverSender = new ServerSender();
     private final ConsoleSender consoleSender = new ConsoleSender();
 
     private final CommandDispatcher dispatcher = new CommandDispatcher();
@@ -154,7 +156,8 @@ public final class CommandManager {
      * @param command the raw command string (without the command prefix)
      * @return true if the command hadn't been cancelled and has been successful
      */
-    public boolean execute(@NotNull CommandSender sender, @NotNull String command) {
+    @Nullable
+    public NBTCompound execute(@NotNull CommandSender sender, @NotNull String command) {
 
         // Command event
         if (sender instanceof Player) {
@@ -164,7 +167,7 @@ public final class CommandManager {
             player.callEvent(PlayerCommandEvent.class, playerCommandEvent);
 
             if (playerCommandEvent.isCancelled())
-                return false;
+                return null;
 
             command = playerCommandEvent.getCommand();
         }
@@ -173,9 +176,9 @@ public final class CommandManager {
 
         {
             // Check for rich-command
-            final boolean result = this.dispatcher.execute(sender, command);
-            if (result) {
-                return true;
+            final NBTCompound commandData = this.dispatcher.execute(sender, command);
+            if (commandData != null) {
+                return commandData;
             } else {
                 // Check for legacy-command
                 final String[] splitCommand = command.split(StringUtils.SPACE);
@@ -185,17 +188,28 @@ public final class CommandManager {
                     if (unknownCommandCallback != null) {
                         this.unknownCommandCallback.apply(sender, command);
                     }
-                    return false;
+                    return null;
                 }
 
                 // Execute the legacy-command
                 final String[] args = command.substring(command.indexOf(StringUtils.SPACE) + 1).split(StringUtils.SPACE);
-
-                return commandProcessor.process(sender, commandName, args);
+                commandProcessor.process(sender, commandName, args);
+                return null;
             }
         }
     }
 
+    /**
+     * Executes the command using a {@link ServerSender} to do not
+     * print the command messages, and rely instead on the command return data.
+     * 
+     * @see #execute(CommandSender, String) 
+     */
+    @Nullable
+    public NBTCompound executeServerCommand(@NotNull String command) {
+        return execute(serverSender, command);
+    }
+
     /**
      * Gets the callback executed once an unknown command is run.
      *

src/main/java/net/minestom/server/command/ServerSender.java

@@ -0,0 +1,31 @@
+package net.minestom.server.command;
+
+import net.minestom.server.command.builder.Arguments;
+import net.minestom.server.permission.Permission;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * Sender used in {@link CommandManager#executeServerCommand(String)}.
+ * <p>
+ * Be aware that {@link #sendMessage(String)} is empty on purpose because the purpose
+ * of this sender is to process the data of {@link Arguments#getCommandReturn()}.
+ */
+public class ServerSender implements CommandSender {
+
+    private final Set<Permission> permissions = Collections.unmodifiableSet(new HashSet<>());
+
+    @Override
+    public void sendMessage(@NotNull String message) {
+        // Empty on purpose
+    }
+
+    @NotNull
+    @Override
+    public Set<Permission> getAllPermissions() {
+        return permissions;
+    }
+}

src/main/java/net/minestom/server/command/builder/Arguments.java

@@ -35,6 +35,8 @@ public final class Arguments {
 
     private Map<String, Object> args = new HashMap<>();
 
+    private NBTCompound commandReturn;
+
     @NotNull
     public <T> T get(@NotNull Argument<T> argument) {
         return (T) getObject(argument.getId());
@@ -250,6 +252,15 @@ public final class Arguments {
         });
     }
 
+    @Nullable
+    public NBTCompound getCommandReturn() {
+        return commandReturn;
+    }
+
+    public void setCommandReturn(@Nullable NBTCompound commandReturn) {
+        this.commandReturn = commandReturn;
+    }
+
     protected void setArg(@NotNull String id, Object value) {
         this.args.put(id, value);
     }

src/main/java/net/minestom/server/command/builder/CommandDispatcher.java

@@ -8,6 +8,7 @@ import net.minestom.server.command.builder.exception.ArgumentSyntaxException;
 import org.apache.commons.lang3.StringUtils;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import org.jglrxavpok.hephaistos.nbt.NBTCompound;
 
 import java.util.*;
 import java.util.regex.Pattern;
@@ -79,18 +80,19 @@ public class CommandDispatcher {
     }
 
     /**
-     * Check if the command exists, and execute it.
+     * Checks if the command exists, and execute it.
      *
      * @param source        the command source
      * @param commandString the command with the argument(s)
-     * @return true if the command executed successfully, false if the command doesn't exist
+     * @return the command data, null if none
      */
-    public boolean execute(@NotNull CommandSender source, @NotNull String commandString) {
+    @Nullable
+    public NBTCompound execute(@NotNull CommandSender source, @NotNull String commandString) {
         CommandResult result = parse(commandString);
         if (result != null) {
-            result.execute(source, commandString);
+            return result.execute(source, commandString);
         }
-        return result != null;
+        return null;
     }
 
     @NotNull
@@ -377,8 +379,10 @@ public class CommandDispatcher {
          *
          * @param source        the command source
          * @param commandString the command string
+         * @return the command data, null if none
          */
-        public void execute(@NotNull CommandSender source, @NotNull String commandString) {
+        @Nullable
+        public NBTCompound execute(@NotNull CommandSender source, @NotNull String commandString) {
             // Global listener
             command.globalListener(source, arguments, commandString);
             // Command condition check
@@ -386,7 +390,7 @@ public class CommandDispatcher {
             if (condition != null) {
                 final boolean result = condition.canUse(source, commandString);
                 if (!result)
-                    return;
+                    return null;
             }
             // Condition is respected
             if (executor != null) {
@@ -408,6 +412,8 @@ public class CommandDispatcher {
                 // Execute the faulty argument callback
                 callback.apply(source, argumentSyntaxException);
             }
+
+            return arguments.getCommandReturn();
         }
 
     }